WO2003076096A1 - Heating apparatus for formable metals - Google Patents

Heating apparatus for formable metals Download PDF

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Publication number
WO2003076096A1
WO2003076096A1 PCT/SG2003/000050 SG0300050W WO03076096A1 WO 2003076096 A1 WO2003076096 A1 WO 2003076096A1 SG 0300050 W SG0300050 W SG 0300050W WO 03076096 A1 WO03076096 A1 WO 03076096A1
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WO
WIPO (PCT)
Prior art keywords
metal
heating
temperature
heat
current temperature
Prior art date
Application number
PCT/SG2003/000050
Other languages
French (fr)
Inventor
Bang Hong Hu
Ming Shyan Yong
Chee Mun Choy
Original Assignee
Singapore Institute Of Manufacturing Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Singapore Institute Of Manufacturing Technology filed Critical Singapore Institute Of Manufacturing Technology
Priority to AU2003217145A priority Critical patent/AU2003217145A1/en
Publication of WO2003076096A1 publication Critical patent/WO2003076096A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/053—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure characterised by the material of the blanks
    • B21D26/055—Blanks having super-plastic properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C29/00—Cooling or heating work or parts of the extrusion press; Gas treatment of work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C9/00—Cooling, heating or lubricating drawing material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00—Tools as parts of machines covered by this subclass
    • B21D37/16—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
    • B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K29/00—Arrangements for heating or cooling during processing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/34—Methods of heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • F27B9/062—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated electrically heated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/004—Heating the product
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D11/00—Process control or regulation for heat treatments
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0003—Monitoring the temperature or a characteristic of the charge and using it as a controlling value

Definitions

  • the present invention relates generally to a heating apparatus for formable metals.
  • the invention relates to a progressive heating apparatus and method for heating formable metals.
  • Background Metals can be fabricated using a variation of techniques, for example forming. Depending on the characteristics of the metal to be fabricated, some metals, for example magnesium, requires pre-heating before substantial forming can be performed.
  • the die of the forming machine can be pre-heated before forming the metal.
  • the unevenness of the face of the die that is used for conducting heat to the metal will result in non-uniform temperature distribution throughout the portion of the metal to be formed. Thermal stresses may be established in the die as a result of temperature gradients across the work-piece, which may lead to a short die lifespan.
  • a pre-fabricated work-piece made of formable metal is usually planar and elongated.
  • a heating apparatus comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and a transfer apparatus for removing the first portion of the metal away from the heating position.
  • a heating apparatus comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; a controller for determining an amount of heat necessary for application to the metal so that the current temperature of the metal substantially conforms to a set-point temperature; and a transfer apparatus for removing the first portion of the metal away from the heating position and positioning the second portion of the metal at the heating position.
  • a heating method comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and removing the first portion of the metal away from the heating position by a transfer apparatus.
  • a heating method comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; determining an amount of heat necessary for application to the metal by a controller so that the current temperature of the metal substantially conforms to a set- point temperature; and removing the first portion of the metal away from the heating position by a transfer apparatus; and positioning the second portion of the metal at the heating position by the transfer apparatus.
  • FIG. 1 is a front view of a heating apparatus with a first portion of a metal positioned at a heating position and a pair of conducting plates in a close position;
  • FIG. 2 is a plan view of the heating apparatus of FIG. 1;
  • FIG. 3 is a front view of the heating apparatus of FIG. 1 with the first position of the metal being fabricated by a process equipment, a second portion of the metal positioned at the heating position and the pair of conducting plates in an open position.
  • the heating apparatus is preferably for heating magnesium alloys prior to fabrication.
  • Magnesium has, as its most outstanding characteristic, the lowest density of all structural metals. Magnesium is therefore used where weight is an important consideration, for example as a material for fabricating mobile phone covers. Magnesium is relatively soft and has a low elastic modulus due to its hexagonal close- packed (HCP) crystal structure.
  • HCP hexagonal close- packed
  • magnesium and its alloys are difficult to deform at room temperature and only small degrees of cold work may be imposed without annealing.
  • Most fabrication of magnesium alloys is either by casting at temperatures above 600 degrees celcius, warm forming, super-plastic forming or forging at temperatures between 200 and 350 degrees celcius.
  • the heating apparatus used in conjunction with processes for warm forming, super-plastic forming or forging of magnesium.
  • the heating apparatus 20 comprises of a pair of conducting plates 22.
  • Each conducting plate 22 is block-shaped and has a metal mating face 24, the metal mating face 24 being planar.
  • the conducting plate 22 has a pair of outwardly opposing side faces 26 generally perpendicular to the metal mating face 24.
  • a plurality of heating conduits 28 extends from one side face 26 to the other side face 26 and having a central axis being generally parallel to the metal mating face 24. Each heating conduit 28 is shaped and dimensioned to accommodate a heating element 30 therein.
  • a plurality of temperature transducer conduits 32 extends from the metal mating face 24 through the conducting plate 22. Each temperature transducer conduit 32 is shaped and dimensioned for receiving a temperature transducer 34 therethrough.
  • Each heating element 30 is electrically connected to a controller (not shown) and for providing heat to the conducting plate 22.
  • the pair of conducting plates 22 is coupled to a clamping assembly 38 with the metal mating face 24 of one conducting plate 22 opposing and spaced apart from the metal mating face 24 of the other conducting plate 22.
  • the clamping assembly 38 cooperates with conducting plates 22 for reciprocating the conducting plates 22 in opposing directions along an axis perpendicular to the metal mating face 24.
  • the clamping assembly 38 is electrically connected to the controller, the controller for controlling the clamping assembly 38 to position the conducting plates 22 at either an open position, as shown in a front view of the heating apparatus 20 in FIG. 3, or a close position as shown in FIG. 1. In the open position, the conducting plates 22 are spaced apart for the passage of a metal 40 therebetween.
  • the metal 40 is preferably magnesium alloy, the metal 40 being planar and elongated in shape.
  • the metal 40 is held by a transfer apparatus 41 with a first portion 42 of the metal 40 in a heating position (not shown) between the pair of conducting plates 22.
  • the clamping assembly 38 brings the conducting plates 22 to the close position. In the close position, the metal mating face 24 of each conducting plate 22 abuts the metal 40.
  • the controller proceeds to transmit a heating signal (not shown) to the heating elements 30.
  • the heating elements 30 generate heat when the heating signal is received from the controller.
  • the conducting plates 22 conduct heat from the heating elements 30 to the first portion 42 of the metal 40.
  • the conducting plates 22 are shaped and dimensioned for evenly heating the first portion 42 of the metal 40.
  • the first portion 42 of the metal 40 has a temperature that is sensed by the temperature transducers 34.
  • the temperature transducers 34 produce a temperature signal (not shown) being representative of the temperature of the first portion 42 of the metal 40 for transmission to the controller.
  • the controller compares the temperature signal with a set-point temperature (not shown) that is pre-defined by a user of the heating apparatus 20.
  • the controller When the temperature of the first portion 42 of the metal 40 is lower than the set-point temperature, the controller continues to transmit the heating signal to the heating elements 30. The controller stops transmitting the heating signal to the heating elements 30 when the temperature of the first portion 42 of the metal 40 reaches the set-point temperature.
  • a mathematical function is used to generate a temperature margin (not shown) based on the size and dimension of the conducting plates 22, the quantity of heating elements 30 utilised in the heating apparatus 20 and the size and dimension of the metal 40.
  • the controller obtains a temperature difference between the temperature of the first portion 42 of the metal 40 and the set- point temperature. When the temperature difference matches the temperature margin, the controller stops transmitting the heating signal to the heating elements 30.
  • the controller Upon the temperature of the first portion 42 of the metal 40 reaching the set-point temperature, the controller signals the clamping assembly 38 to position the conducting plates 22 in the open position. The transfer apparatus 41 then proceeds to remove the first portion 42 of the metal 40 from the heating position. The first portion 42 of the metal transferred to a process equipment 48 for fabrication.
  • the process equipment 48 is preferably a forming machine that requires the metal 40 to be at a formable temperature approximated by the set-point temperature.
  • the temperature of the second portion 50 of the metal has already achieve a portion of the set-point temperature through conduction when the first portion 42 of the metal 40 is being heated by the conducting plates 22. Therefore, it will require a shorter period of time for the temperature of the second portion 50 of the metal 40 to reach the set- point temperature when heated by the conducting plates 22.
  • the aforementioned heating method not only requires a shorter heating time, but also reduces thermal shock induced when too much heat is introduced into the metal 40 within a short time period. This is achieved by progressive heating of the metal 40 using the heating apparatus 20 by segregating the heating process: first by heating the second portion 50 of the metal 40 by conducting heat from the first portion 42 of the metal 40 that is being heated, consequentially by directly heating the partially heated second portion 50 of the metal 40 to the set-point temperature.
  • a heating apparatus and method is described according to an embodiment of the invention for addressing the foregoing disadvantages of conventional heat treatment methods and apparatus.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
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Abstract

Some metals, for example magnesium alloy, require pre-heating prior to fabrication processes such as forming. A conventional pre-heating practice of placing these metals in furnaces is time-consuming. An alternative practice of pre-heating the die of a forming maching may result in shortening the lifespan of the die or lowering the productivity of a production line. The invention achieves shorter heating time and reduces thermal shock induced, by heating the metal progressively using a heating apparatus. The heating process of a metal is segregated: first, by heating a second portion of a metal by conducting heat from a first portion of the metal that is being heated, and next, by directly heating the partially heated second protion of the metal to a formable temperature.

Description

A HEATING APPARATUS FOR FORMABLE METALS
Field Of Invention
The present invention relates generally to a heating apparatus for formable metals. In particular, the invention relates to a progressive heating apparatus and method for heating formable metals.
Background Metals can be fabricated using a variation of techniques, for example forming. Depending on the characteristics of the metal to be fabricated, some metals, for example magnesium, requires pre-heating before substantial forming can be performed.
Conventionally, a work-piece made from one of these metals has to be placed into a furnace prior to being fabricated. However, this is a time-consuming process that does not meet the high throughput requirement of a production line. The use of a furnace for heating up the work-piece is time consuming. The need for transfer of the work-piece between the furnace and a forming machme is inefficient when speed is required, especially along a production line.
Alternatively, the die of the forming machine can be pre-heated before forming the metal. However, the unevenness of the face of the die that is used for conducting heat to the metal will result in non-uniform temperature distribution throughout the portion of the metal to be formed. Thermal stresses may be established in the die as a result of temperature gradients across the work-piece, which may lead to a short die lifespan.
Hence, this clearly affirms a need for a heating apparatus and method for improving the pre-heating process of a formable metal. Summary
A pre-fabricated work-piece made of formable metal is usually planar and elongated.
When directly heating a first portion of the work-piece, an adjacent second portion of the work-piece is heated as well through conduction. Consecutively, when the second portion of the work-piece heated, only a short period of time is required for the second portion of the work-piece to achieve a required temperature.
Therefore, in accordance with a first aspect of the invention, there is disclosed a heating apparatus comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and a transfer apparatus for removing the first portion of the metal away from the heating position.
In accordance to a second aspect of the invention, there is disclosed a heating apparatus comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; a controller for determining an amount of heat necessary for application to the metal so that the current temperature of the metal substantially conforms to a set-point temperature; and a transfer apparatus for removing the first portion of the metal away from the heating position and positioning the second portion of the metal at the heating position.
In accordance to a third aspect of the invention, there is disclosed a heating method comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and removing the first portion of the metal away from the heating position by a transfer apparatus.
In accordance to a fourth aspect of the invention, there is disclosed a heating method comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; determining an amount of heat necessary for application to the metal by a controller so that the current temperature of the metal substantially conforms to a set- point temperature; and removing the first portion of the metal away from the heating position by a transfer apparatus; and positioning the second portion of the metal at the heating position by the transfer apparatus.
Brief Description Of The Drawings
Embodiments of the invention are described hereinafter with reference to the following drawings, in which:
FIG. 1 is a front view of a heating apparatus with a first portion of a metal positioned at a heating position and a pair of conducting plates in a close position;
FIG. 2 is a plan view of the heating apparatus of FIG. 1; and
FIG. 3 is a front view of the heating apparatus of FIG. 1 with the first position of the metal being fabricated by a process equipment, a second portion of the metal positioned at the heating position and the pair of conducting plates in an open position.
Detailed Description
A heating apparatus and method for addressing the foregoing problems is described hereinafter.
The heating apparatus is preferably for heating magnesium alloys prior to fabrication. Magnesium has, as its most outstanding characteristic, the lowest density of all structural metals. Magnesium is therefore used where weight is an important consideration, for example as a material for fabricating mobile phone covers. Magnesium is relatively soft and has a low elastic modulus due to its hexagonal close- packed (HCP) crystal structure. However, magnesium and its alloys are difficult to deform at room temperature and only small degrees of cold work may be imposed without annealing. Most fabrication of magnesium alloys is either by casting at temperatures above 600 degrees celcius, warm forming, super-plastic forming or forging at temperatures between 200 and 350 degrees celcius. The heating apparatus used in conjunction with processes for warm forming, super-plastic forming or forging of magnesium.
An embodiment of the invention, a heating apparatus 20 is described with reference to
FIG. 1, which shows a front view of the heating apparatus 20, and FIG. 2, which shows a plan view of the heating apparatus 20. The heating apparatus 20 comprises of a pair of conducting plates 22. Each conducting plate 22 is block-shaped and has a metal mating face 24, the metal mating face 24 being planar. The conducting plate 22 has a pair of outwardly opposing side faces 26 generally perpendicular to the metal mating face 24.
A plurality of heating conduits 28 extends from one side face 26 to the other side face 26 and having a central axis being generally parallel to the metal mating face 24. Each heating conduit 28 is shaped and dimensioned to accommodate a heating element 30 therein. A plurality of temperature transducer conduits 32, as shown in FIG. 2, extends from the metal mating face 24 through the conducting plate 22. Each temperature transducer conduit 32 is shaped and dimensioned for receiving a temperature transducer 34 therethrough.
Each heating element 30 is electrically connected to a controller (not shown) and for providing heat to the conducting plate 22. The pair of conducting plates 22 is coupled to a clamping assembly 38 with the metal mating face 24 of one conducting plate 22 opposing and spaced apart from the metal mating face 24 of the other conducting plate 22. The clamping assembly 38 cooperates with conducting plates 22 for reciprocating the conducting plates 22 in opposing directions along an axis perpendicular to the metal mating face 24.
The clamping assembly 38 is electrically connected to the controller, the controller for controlling the clamping assembly 38 to position the conducting plates 22 at either an open position, as shown in a front view of the heating apparatus 20 in FIG. 3, or a close position as shown in FIG. 1. In the open position, the conducting plates 22 are spaced apart for the passage of a metal 40 therebetween. The metal 40 is preferably magnesium alloy, the metal 40 being planar and elongated in shape.
The metal 40 is held by a transfer apparatus 41 with a first portion 42 of the metal 40 in a heating position (not shown) between the pair of conducting plates 22. In response to the first portion 42 of the metal 40 being placed in the heating position, the clamping assembly 38 brings the conducting plates 22 to the close position. In the close position, the metal mating face 24 of each conducting plate 22 abuts the metal 40.
The controller proceeds to transmit a heating signal (not shown) to the heating elements 30. The heating elements 30 generate heat when the heating signal is received from the controller. The conducting plates 22 conduct heat from the heating elements 30 to the first portion 42 of the metal 40. The conducting plates 22 are shaped and dimensioned for evenly heating the first portion 42 of the metal 40.
The first portion 42 of the metal 40 has a temperature that is sensed by the temperature transducers 34. The temperature transducers 34 produce a temperature signal (not shown) being representative of the temperature of the first portion 42 of the metal 40 for transmission to the controller. The controller compares the temperature signal with a set-point temperature (not shown) that is pre-defined by a user of the heating apparatus 20.
When the temperature of the first portion 42 of the metal 40 is lower than the set-point temperature, the controller continues to transmit the heating signal to the heating elements 30. The controller stops transmitting the heating signal to the heating elements 30 when the temperature of the first portion 42 of the metal 40 reaches the set-point temperature.
Alternatively, a mathematical function is used to generate a temperature margin (not shown) based on the size and dimension of the conducting plates 22, the quantity of heating elements 30 utilised in the heating apparatus 20 and the size and dimension of the metal 40. Using a comparator (not shown), the controller obtains a temperature difference between the temperature of the first portion 42 of the metal 40 and the set- point temperature. When the temperature difference matches the temperature margin, the controller stops transmitting the heating signal to the heating elements 30.
Upon the temperature of the first portion 42 of the metal 40 reaching the set-point temperature, the controller signals the clamping assembly 38 to position the conducting plates 22 in the open position. The transfer apparatus 41 then proceeds to remove the first portion 42 of the metal 40 from the heating position. The first portion 42 of the metal transferred to a process equipment 48 for fabrication. The process equipment 48 is preferably a forming machine that requires the metal 40 to be at a formable temperature approximated by the set-point temperature.
When the first portion 42 of the metal 40 is being heated, heat is conducted from the first portion 42 to a second portion 50 of the metal 40. The second portion 50 is adjacent to the first portion 42 of the metal 40. Removing the first portion 42 of the metal 40 from the heating position by the transfer apparatus 41 consequently positions the second portion 50 of the metal 40 at the heating position.
The temperature of the second portion 50 of the metal has already achieve a portion of the set-point temperature through conduction when the first portion 42 of the metal 40 is being heated by the conducting plates 22. Therefore, it will require a shorter period of time for the temperature of the second portion 50 of the metal 40 to reach the set- point temperature when heated by the conducting plates 22.
The aforementioned heating method not only requires a shorter heating time, but also reduces thermal shock induced when too much heat is introduced into the metal 40 within a short time period. This is achieved by progressive heating of the metal 40 using the heating apparatus 20 by segregating the heating process: first by heating the second portion 50 of the metal 40 by conducting heat from the first portion 42 of the metal 40 that is being heated, consequentially by directly heating the partially heated second portion 50 of the metal 40 to the set-point temperature. In the foregoing manner, a heating apparatus and method is described according to an embodiment of the invention for addressing the foregoing disadvantages of conventional heat treatment methods and apparatus. Although only one embodiment of the invention is disclosed, it will be apparent to one skilled in the art in view of this disclosure that numerous changes and/or modification can be made without departing from the scope and spirit of the invention.

Claims

Claims
1. A heating apparatus for formable metals comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and a transfer apparatus for removing the first portion of the metal away from the heating position.
2. The heating apparatus as in claim 1, the temperature transducer unit comprising: an array of temperature transducers for sensing the current temperature of the first portion of the metal, each temperature transducer for mounting onto the first portion of the metal.
3. The heating apparatus as in any of claims 1 and 2, the heating unit comprising: one or more conducting plates for mounting onto the first portion of the metal; and one or more heating elements received in each conducting plate for providing heat to the conducting plate, the conducting plate conducting heat to the first portion of the metal by conduction.
4. The heating apparatus as in claim 3, each conducting plate comprising: a metal mating face for contact with the metal, the metal being generally planar; and a plurality of generally cylindrical conduit extending from the metal mating face through the conducting plate, each conduit having a central axis generally perpendicular to the metal mating face and for the passage of a corresponding temperature transducer therethrough to couple the corresponding temperature transducer to the conducting plate.
The heating apparatus as in claim 1, the heating unit comprising: a pair of conducting plates arranged for reciprocating in opposing directions and for cooperating to clamp the first portion of the metal therebetween; and one or more heating elements received in each conducting plate for providing heat to the conducting plate, the conducting plate conducting heat to the first portion of the metal.
The heating apparatus as in any of claims 1 and 4, further comprising: a controller for determining an amount of heat necessary for application to the first portion of the metal so that the current temperature of the metal substantially conforms to a set-point temperature, the set-point temperature being defined by a user, and the controller being electrically connected to both the heating unit and the temperature transducer, the controller for receiving the current temperature signal from the temperature transducer, and for providing a heating signal to the heating unit.
The heating apparatus as in claim 6, the controller comprising: a comparator for obtaining a temperature difference between the set- point temperature and the current temperature, wherein the controller provides a heating signal to the heating elements when the temperature difference is higher than a threshold value, the threshold value being defined by the user and the heating elements providing heat when the heating signal is received.
The heating apparatus as in claim 6, wherein the controller provides a heating signal to the heating elements when the set-point temperature is higher than the current temperature, the heating elements providing heat when the heating signal is received.
The heating apparatus as in any of claims 1, 7 and 8, wherein the first portion of the metal conducts heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal, and the second portion of the metal being positioned at the heating position when the first portion of the metal is removed from the same by the transfer apparatus.
10. A heating apparatus for formable metals comprising: a heating unit for applying an amount of heat to a first portion of a metal, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; a temperature transducer unit for sensing the current temperature of the first portion of the metal, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; a controller for determining an amount of heat necessary for application to the metal so that the current temperature of the metal substantially conforms to a set-point temperature; and a transfer apparatus for removing the first portion of the metal away from the heating position and positioning the second portion of the metal at the heating position.
11. A heating method for formable metals comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer unit for producing a current temperature signal representative of the current temperature of the first portion of the metal; and removing the first portion of the metal away from the heating position by a transfer apparatus.
12. The heating method as in claim 11, further comprising the step of: providing an array of temperature transducers for sensing the current temperature of the first portion of the metal, each temperature transducer being received in the temperature transducer unit and for mounting onto the first portion of the metal.
13. The heating method as in any of claims 11 and 12, wherein the heating unit comprising: one or more conducting plates for mounting onto the first portion of the metal; and one or more heating elements received in each conducting plate for providing heat to the conducting plate, the conducting plate conducting heat to the first portion of the metal by conduction.
14. The heating method as in claim 13, wherein each conducting plate comprising: a metal mating face for contact with the metal, the metal being generally planar; and a plurality of generally cylindrical conduit extending from the metal mating face through the conducting plate, each conduit having a central axis generally perpendicular to the metal mating face and for the passage of a corresponding temperature transducer therethrough to couple the corresponding temperature transducer to the conducting plate.
15. The heating method as in claim 11, wherein the heating unit comprising: a pair of conducting plates arranged for reciprocating in opposing directions and for cooperating to clamp the first portion of the metal therebetween; and one or more heating elements received in each conducting plate for providing heat to the conducting plate, the conducting plate conducting heat to the first portion of the metal.
16. The heating method as in any of claims 11 and 14, further comprising the step of: W
13 providing a controller for determining an amount of heat necessary for application to the first portion of the metal so that the current temperature of the metal substantially conforms to a set-point temperature, the set-point temperature being defined by a user, and the controller being electrically connected to both the heating unit and the temperature transducer, the controller for receiving the current temperature signal from the temperature transducer, and for providing a heating signal to the heating unit.
17. The heating method as in claim 16, further comprising the steps of: obtaining a temperature difference between the set-point temperature and the current temperature by a comparator, the comparator being received in the controller; and providing a heating signal from the controller to the heating elements when the temperature difference is higher than a threshold value, the threshold value being defined by the user and the heating elements providing heat when the heating signal is received.
18. The heating method as in claim 16, further comprising the step of: providing a heating signal from the controller to the heating elements when the set-point temperature is higher than the current temperature, the heating elements providing heat when the heating signal is received.
19. The heating method as in any of claims 11, 17 and 18, further comprising the steps of: conducting heat from the first portion of the metal to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; and positioning the second portion of the metal at the heating position when the first portion of the metal is removed from the same by the transfer apparatus.
20. A heating method for formable metals comprising the steps of: applying an amount of heat to a first portion of a metal by a heating unit, the first portion of the metal having a current temperature and being positioned at a heating position, the amount of heat increasing the current temperature of the first portion of the metal and the first portion of the metal conducting heat to a second portion of the metal, the second portion of the metal being adjacent to the first portion of the metal; sensing the current temperature of the first portion of the metal by a temperature transducer unit, the temperature transducer for producing a current temperature signal representative of the current temperature of the first portion of the metal; determining an amount of heat necessary for application to the metal by a controller so that the current temperature of the metal substantially conforms to a set-point temperature; and removing the first portion of the metal away from the heating position by a transfer apparatus; and positioning the second portion of the metal at the heating position by the transfer apparatus.
PCT/SG2003/000050 2002-03-14 2003-03-13 Heating apparatus for formable metals WO2003076096A1 (en)

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CN102500635A (en) * 2011-10-11 2012-06-20 福建工程学院 Magnesium alloy heating and forming process and magnesium alloy heating and feeding channel
CN102688907A (en) * 2011-03-24 2012-09-26 大连交通大学 System and method for continuous extrusion production of fine-grain magnesium alloy strip
CN103212617A (en) * 2013-04-18 2013-07-24 重庆市科学技术研究院 Automatic production method of magnesium alloy plate in hot stamping forming mode
CN105149377A (en) * 2015-09-30 2015-12-16 中镁镁业有限公司 On-line hot air heating device and heating and winding method for magnesium alloy extrusion plates
WO2019015928A1 (en) 2017-07-21 2019-01-24 Adval Tech Holding Ag Method and device for shaping magnesium metal sheet and components produced therewith
CN112916777A (en) * 2020-12-28 2021-06-08 东北轻合金有限责任公司 Manufacturing method of high-formability magnesium alloy forging for spaceflight

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Publication number Priority date Publication date Assignee Title
WO2011148183A1 (en) * 2010-05-27 2011-12-01 Luxfer Group Limited Method and apparatus for fabricating articles from metals having a hexagonal close packed crystal structure
WO2012055688A1 (en) * 2010-10-27 2012-05-03 Thyssenkrupp Steel Europe Ag Process and installation for producing a component from sheet magnesium
CN102688907A (en) * 2011-03-24 2012-09-26 大连交通大学 System and method for continuous extrusion production of fine-grain magnesium alloy strip
CN102500635A (en) * 2011-10-11 2012-06-20 福建工程学院 Magnesium alloy heating and forming process and magnesium alloy heating and feeding channel
CN103212617A (en) * 2013-04-18 2013-07-24 重庆市科学技术研究院 Automatic production method of magnesium alloy plate in hot stamping forming mode
CN105149377A (en) * 2015-09-30 2015-12-16 中镁镁业有限公司 On-line hot air heating device and heating and winding method for magnesium alloy extrusion plates
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CN112916777A (en) * 2020-12-28 2021-06-08 东北轻合金有限责任公司 Manufacturing method of high-formability magnesium alloy forging for spaceflight

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